The IgG antibody response against polysaccharide microbial antigens is enriched for IgG2 antibodies. Lower IgG2 concentration has been found to be a risk factor of death after community acquired pneumonia. Infection is a major cause of death during the first year after heart transplantation. We evaluated the prevalence of IgG2 insufficiency in heart recipients before transplantation and its relationship with the risk for development of severe early deadly infections.
119 patients evaluated in a single center were included. IgG2 assessment was performed at the time of inclusion in waiting list. Prospective follow-up was performed to identify early deadly infections during the first month after transplantation (n=11, mainly bacterial infections). Definitions: IgG2 deficiency, IgG2 <115 mg/dL; IgG2 insufficiency, IgG2 115-272 mg/dL.
Forty-six (38.7%) patients disclosed IgG2 insufficiency. Early deadly infections were more prevalent among patients with IgG2 insufficiency (RH 2.68, 95% CI 1.10-6.53, p=0.029). Use of mechanical ventilation, pre-transplant infections and pre transplant use of ventricular assist devices were risk factors of early deadly infections. In multivariate regression analysis IgG2 insufficiency remained in the model (RH 4.18, 95% CI 1.20-14.47, p=0.024). IgG anti-pneumococcal polysaccharide antibody levels were significantly lower in patients with IgG2 insufficiency before transplantation, at day 7 and day 30 after transplantation.
Pre-transplant IgG2 insufficiency is a risk factor of early deadly infection after heart transplantation. This new immunological definition warrants evaluation in a multicenter study.